Netgear C7000v2 Randomly Losing Connection

Question

I've lived in my condo complex for almost two years, and I've had Xfinity and my own Netgear C7000v2 modem/router since I moved in. I've never once had to restart the router until I suddenly lost connection on all of my devices during a Zoom call about a month ago. That night, the internet would go down, I'd reset the router, it would work for a bit, and then it would go down again. It's happened once or twice since then.

Firmware Version: V1.03.01

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	579000000 Hz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enabled	BPI+
IP Provisioning Mode	Honor MDD	honorMdd(4)

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectables
1	Locked	QAM256	21	579000000 Hz	6 dBmV	41.8 dB	3	0
2	Locked	QAM256	17	555000000 Hz	4.8 dBmV	41.3 dB	2	0
3	Locked	QAM256	18	561000000 Hz	4.5 dBmV	40.3 dB	2	0
4	Locked	QAM256	19	567000000 Hz	4.7 dBmV	41.2 dB	1	0
5	Locked	QAM256	20	573000000 Hz	5.4 dBmV	41.5 dB	1	0
6	Locked	QAM256	25	603000000 Hz	4.5 dBmV	40.3 dB	0	0
7	Locked	QAM256	22	585000000 Hz	6.2 dBmV	41.6 dB	3	0
8	Locked	QAM256	23	591000000 Hz	6 dBmV	41.4 dB	2	0
9	Locked	QAM256	24	597000000 Hz	5.3 dBmV	40.9 dB	2	0
10	Locked	QAM256	26	609000000 Hz	3.3 dBmV	40 dB	4	0
11	Locked	QAM256	27	615000000 Hz	3.1 dBmV	39.9 dB	4	0
12	Locked	QAM256	28	621000000 Hz	3 dBmV	40.1 dB	3	0
13	Locked	QAM256	29	627000000 Hz	5.2 dBmV	40.9 dB	2	0
14	Locked	QAM256	30	633000000 Hz	5.9 dBmV	41.6 dB	1	0
15	Locked	QAM256	31	639000000 Hz	4.9 dBmV	40.4 dB	2	0
16	Locked	QAM256	32	645000000 Hz	4.5 dBmV	40.6 dB	3	0
17	Locked	QAM256	33	651000000 Hz	3.6 dBmV	40.8 dB	0	0
18	Locked	QAM256	34	657000000 Hz	4 dBmV	40.8 dB	0	0
19	Locked	QAM256	35	663000000 Hz	4.2 dBmV	40.8 dB	0	0
20	Locked	QAM256	36	669000000 Hz	4.6 dBmV	41.3 dB	0	0
21	Locked	QAM256	37	675000000 Hz	4.9 dBmV	40.9 dB	0	0
22	Locked	QAM256	38	681000000 Hz	4.7 dBmV	41.4 dB	0	0
23	Locked	QAM256	39	687000000 Hz	4.6 dBmV	40.9 dB	0	0
24	Locked	QAM256	40	693000000 Hz	4.4 dBmV	40.9 dB	0	0

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	1	5120 Ksym/sec	36500000 Hz	44.5 dBmV
2	Locked	ATDMA	2	5120 Ksym/sec	30100000 Hz	44.5 dBmV
3	Locked	ATDMA	3	5120 Ksym/sec	23700000 Hz	44.5 dBmV
4	Locked	ATDMA	4	5120 Ksym/sec	17300000 Hz	44.5 dBmV
5	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV
6	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV
7	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV
8	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV

Event Log

Time	Priority	Description
1970-1-1, 00:00:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-12-21, 02:16:15	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-12-21, 02:16:15	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-12-20, 17:17:37	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-12-20, 17:05:50	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:46	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-11-29, 20:37:52	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-11-29, 20:26:05	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:45	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-11-29, 20:22:55	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:45	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-10-7, 16:33:08	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:43	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-9-1, 11:34:22	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-8-27, 13:46:40	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-8-27, 13:46:38	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-8-27, 13:46:27	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-8-27, 13:46:22	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
2020-8-24, 02:57:58	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:37	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-8-8, 21:26:00	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-8-8, 05:58:14	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-8-6, 19:23:11	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-6-30, 14:28:54	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:37	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-6-22, 23:50:50	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:15:a6:50;CMTS-MAC=58:97:bd:98:40:ea;CM-QOS=1.1;CM-VER=3.0;

I'm happy to provide more information - I'm just frustrated as I've never had any issues.

EG · Answer

The signal status values are o/k, the error log entries, not so much...

Are these WiFi connections ? If so, for a test, does a computer / device hardwired directly to the C7000 with an ethernet cable have the same problem ?

With this test, we are trying to isolate this from being either a WiFi-only problem or a problem with the general connection to the Comcast system which would of course affect both. It's a good first step of troubleshooting before we proceed any further

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jwarren90

Netgear C7000v2 Randomly Losing Connection

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EG

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